The aerodynamics of a helicopter undergoing steady-state maneuvers has been studied using a free-vortex model of the rotor wake. The wake model is based on a finite-difference approximation to the vorticity transport equation, and is solved using a pseudo-implicit relaxation method. It is shown that, in both hover and forward flight, maneuvers are a source of additional distortion to the vortical rotor wake. This wake distortion can be sensitive to the maneuvering rates. In hover and low speed forward flight, the maneuver induced wake distortion manifest as a counter intuitive change in inflow velocity through the rotor. This suggests that the free wake dynamics during pitching and rolling maneuvers may manifest as a contributor to the 'off-axis' blade flapping response. At higher advance ratios, the effects of maneuver induced wake distortions are still present, but are reduced by about half relative to the hover condition. The results provide guidelines as to the importance of the main rotor wake in predicting the rotor flapping response during maneuvers.


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    Title :

    Aerodynamics analysis of a helicopter in steady maneuvering flight using a free-vortex rotor wake model


    Additional title:

    Die aerodynamische Analyse eines Helikopters im stationären Manöverflug mit einem Rotor-Frei-Wirbelströmungsmodell


    Contributors:
    Bagai, A. (author) / Leishman, J.G. (author) / Park, J. (author)

    Published in:

    Publication date :

    1999


    Size :

    12 Seiten, 15 Bilder, 31 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English





    ROTOR AERODYNAMICS DURING MANEUVERING FLIGHT USING A TIME-ACCURATE FREE-VORTEX WAKE

    Bhagwat, M. J. / Leishman, J. G. / American Helicopter Society | British Library Conference Proceedings | 2001




    Rotor Wake Aerodynamics in Large Amplitude Maneuvering Flight

    Ananthan, Shreyas | Online Contents | 2006